Privateer magazine (Rapha's off road sibling) has a great 12 page feature on the Polaris Challenge http://www.rouleur.cc/privateer 

The magazine features a great piece on past 'faces' of the event, how it came about and the organisation behind it. It also features a host of great images from past events.

If you fancy subscribing to the mag here is a great Polaris '4 for 3' deal